Throttle valve



July 14, 1936.,

G. A. cR sBY THROTTLE VALVE Filed aul 'zs, 1955 bad A 41? WM PM Patented July 14, 1936 STATES PATENT OFFICE THROTTLE VALVE Application July 23, 1935, SerialNo. 32,737

8 Claims.

This invention relates to throttle valves and more particularly to throttle valves intended for use with self-propelled vehicles employing high pressure motive fluid where it may be required .to move and maintain the valve slightly or partially open or to apply reduced pressure to the motor by finely graduated steps for starting and for operating it at different low-power outputs.

In the case of a steam road vehicle, for example, where a boiler pressure of 700 to 800 pounds or more is common and where the throttle valve is required to control in part or in whole awide range of variations in engine power, it is desirable that the valve should be capable of opening easily under foot or hand pressure. But it should also be capable of being moved and of being held open with but slight effort in any one of the positions representing the entire range of pressures to be applied to the engine, including such low pressures as may be secured by merely fcracking or very slightly opening the valve.

Where a positively seated throttle valve of the poppet type is used, the first object may be attained by employing a so-called pilot valve of reduced cross-sectional area to admit boiler pressure to balance or partially balance the throttle valve and permit it to'be lifted with little efiort. Even if such a pilot valve is employed, however, and it is attempted to use the poppet valve to re- .duce the steam to a low pressure for relatively low engine outputs, the valve will have to be held close to its seat where the throttle is subject to an unbalanced pressure due to the high boiler pressure on one sideof the valve head and the low steam chest pressure on the opposite side of the head. This imparts to it. a closing tendency,

the smaller the valve opening the greater being I such closingtendency and the greater the effort to ofiset it. The result is that the effort required to move the Valve is variable for difierent positions, the position of the valve isuncertain, its movement jerky, and it becomes incapable of smooth, graduated control.

One object of the invention, among others, is to provide a throttle valve which may be opened to any desired position with certainty and under alight pressure by the foot or hand.

' This and other objects of the invention will be best understood by the following description when taken in connection with the accompanying illustration of one specific embodiment thereof, while its scope will bemore particularly pointed out in the appended claims.

In the drawing:

Fig. 1 shows a cross sectional elevation oilth principal parts of the throttle valve embodying one form of the invention; and

Fig. 2 shows the same valve with its actuating parts installed in a road vehicle. t Referring to the drawing and to the embodi- '5 ment of the invention therein shown for illustrative purposes, the throttle device comprises the casing 3 having the steam supply chamber 5 in its upper end to which high pressure steam is admitted from the boiler (not shown) through the steam supply pipe 1 (Fig. 2). Under the control of the throttle steam is delivered to the engine (not shown) through the steam supply pipe 9.

The throttle valve comprises a main self-seating valve head II fitting a tapered seat which may be formed in the casing, or as herein shown is formed in the sleeve l3 which is tightly fixed in the casing.

To lift the valve head II the latter is carried at the end of the hollow sleeve l5 having a sliding fit within the sleeve l3. The sleeve I5 is provided with oneor more (herein two) sets of circumferentially arranged ports H and I9 which, when the valve is sufficiently raised, are adapted to register with an undercut annular space 2| communicating with circumierentially arranged ports 22 in the fixed sleeve l3 and to open the interior of the hollow sleeve I5 to the annular steam delivery chamber 23 and the steam delivery pipe 9 communicating therewith.

Centrally arranged within the main valve head is a second relatively small pilot valve 25 fitting a tapered seat in the valve head H and adapted to be lifted therefrom to open the interior of the sleeve l5 to boiler pressure by means of the upright actuating rod 21 concentrically arranged within the sleeve. The rod 21 extends down through the hollow interior of the sleeve l5, through an underlying chamber 29 in the casing and through a packing box 3|, being provided with an extension 33 depending from the casing and adapted to be controlled by extraneous operating connections.

-Such connections herein (Fig. 2-) comprise the link 35 pivotally connected at its upper end to the rod extension '33 and at its lower end to one arm of the bell-crank lever 31, the latter being pivoted on an arm of a bracket 39 carried by the throttle valve casing. The remaining or upright arm of the bell-crank 31 is connected to the push 5o rod 4| which extends rearwardly. At its end the push rod is provided with a head 43 located in a position above the foot-board 45 of the vehicle where itmay be conveniently controlled by pressure of. thedrivers foot, Fig. 2 indicating merely throttle device of the type herein shown.

When the push rod 4| is first moved, the rod 21 is raised unseating the pilot valve 25 and opening to the high boiler pressure the interior of the hollow sleeve l5 and the chamber 29 to which the lower end of the sleeve is exposed. Beneath the outwardly tapered walls of the main valve head I I the sleeve. l5 has at circumferentially. reduced'pontion providing anannula'r space or chamber 4T between its outer walls and the inner walls of the fixed sleeve it, which space is in free communi a cation with the interior of the sleeve 15 through circumferentially arranged ports49, and is also open to boiler pressure by'theunseating; of the pilot valve 25. V The unseating of" the pilot valve;

therefore, provides a condition of substantial presprises a: but-tonrlike. member: 5 l threadcchonl the radial and having, flanged. walls; whichzunderlie. the. bottom edges of the; sleeve. 15, these; however,

being; slightly; spaced from; the; sleeve when the pilot; valveis; seatedito; permit aisufiicient: op ening" of; thepilot-valve before: movement: of the 1 sleeve. l5.is:initiated.. The lifting member; islheld; in: fixed gposition-pnthe:rndzby; the lock. nutlfiiwhich however,lmrmitse its. adjustment thereby; to; vary. as-;des-ired;the:nonnaLclear-anceibetween its walls andzthe edges-10f: thesleevel. Provision may be madeiifzdesired, as by scoring :Qr'grooving the icon tacting'edges; ofi'thellif-ting member, .to insure :the chamber 29 being at all times in communication witlnthe inter-ior'ofithe sleeve who r V I V V Eollowin'g: the: lifting\ of; thelmainsvalve. III :and sleeve: l5;;t-he ports- [land I 8-; in the sleeve lap proachand: finally'open'thezannular space .21. and ports=.22land;cause steam tolpass fromthe-interior.

. of, theehollow valveito' the deliverytpipe 9, the rate ofsteamfiownand:thepressure appliedztoithe engineobviouslydependingon the zoverlap -between thBiIJQItSQfIthS-SIGQVEr l5 andat-hoseinzthe fixed sleeveaslfiz. The efiect, hdwever; oft thelpressure dropon the deliveryside oil the :valve is-zeliminated as a disturbing factor in the-forcearequired to mnvez'the valve,..;since the. valve head l t. is:permitteditm lift. a" substantial distance before theport l 121': opens the-.port 22,: the :result beingthat, irrespective: of: the extent to which: the portlliiis openedxand ot the; pnessurezon the delivery pipe side-of; the throttle;.the;press11re balance. condis tion'rof thBaVEll/B head all I; and sleeve. l5 remains undisturbed. This permitsthe-fcot'pressurelto be applied on the knob dflland securewithcertaintyany-throttling: position; of the :valve ins its entirerangeof movementwitha-smooth; graduated-con trol ;unaffiecte.d;bythe; pressure drop through thevalve. I

I It; will :beaseen; that: the interion-ofs the hollow sleeve l 5 provides an-intermediate chamber which is-placediin'free,communication with" the pressuresupply chamber :5. by' the opening of the main valve H but; that: this: intermediateichamber iss. normally cut ofi fromtheldeliveryl portszl by-thewallsofltheslowenparttof ithe ;sleevewl1ich1consti#- tute a. throttling valve: capable; or; an graduated throttling. control after; the.=main. valve is openedi. The described formrofithrottling,devicealso has; the; advantage; of; avoiding tire-mooring action of schematically conditions of use in the case of a seating valve is employed to effect the throttling. Such valves tend to become leaky in a very short" -1 time due to the action of the steam under conditions of slight opening or cracking. V In the illustrated embodiment of the invention such scor- 7 ing actionis substantially eliminated. The ported sleeve 15 is preferably made of stainless steel and hardened to'withstand wear andscoring and may 7 7 remain tightindefinitelv. v While I have herein shown for purposes of illustration one specific embodiment of the invention, it is to be understood that extensive devia tions-andydepartures may be made therefrom, all within the spiritof the invention.

1*. A throttlingdevice having a valve casingprovided' with a pressure-fluid supply chamber, a movablehollom sleeve having a sliding fit in said casing, and provided with circumferentially ar-V ranged throttling ports communicating with the 20 hollow inter-ion of the sleeve said; sleeve,- carrying a amain valve'head fitting a tapered seat-insaid supply chamber; saidi device'having an. annular: chamber, exterior the sleeve: adjacent; thev maini head and having also alchamberat the 0pposite25 end. oi. the.-s1eeve, both of which chambers." come municate; with; thehollow. interior of. the sleeve. i

a pilot valveqfittinga tapered seat; in saidam'aim; V

valve head an actuating rod connected tOY'SBjLdV pilot valvepassingv through the :hollow interiorrof 30? with: a throttling, portopening'" into:- the, hollow 5;: V

interion of; the: sleeve; and adapted 1 to bezbrought intoregistration; with .said? delivery port,.a. main-' valve-head carriedhy said'sleeve fittin'gaitapered seat in saidisupply: chamber, .a pilot valvelfittingiattaperedtseat in; said..main -valve; head;-. opening 50-; oil which pilot; valve serves; to bring" said main headrandsaid sleeve-to air-condition ofcsubst'antil pressure; balanca; an; actuating .;device' passing through; saidusleevel unseating and open-ingsaidzpilotzvalve;andimeansomsazid actuatingde 552$ viceito. mowe-..-said;sleevewtfter: the opening of-jsaid" pilot: valve; first:v to gopenl said main valve head I and thereafter: tovsopen said deliveryport to said 7 throttling'port. f 7

3: Althrottling device having a valve-casi-ngififl provided with :a pressureafluid supply chamber: and a-delirrery port; a; movable hol-lbw valve' sleeve having a sliding movement in said-casing and" providedi with a throttling port adapted tobe brought into registration with said d'elivery port; 65" a -main valverhead fitting a tapered seat in said supply chamber, a pilot valve fitting a tapered seatinsaid main valvehead; openingof which serves t'copen the-interiorof thesleeve to-saidsupplycliamber'and to' bring said ina-inheadandiO- T 7 throttling pcrt-to said delivery port;

4. A throttling device having a valve casing provided with a pressure-fluid supply chamber and'a delivery port, a movable hollow valve sleeve having a sliding movement in said casing and provided with a throttling port adapted to be brought into registration with said delivery port, a main valve head fitting a tapered seat in said supply chamber and adapted to open the latter to the hollow interior of the sleeve, a pilot valve, opening of which serves to bring said main valve head to a condition of substantial pressure balance, and actuating means for first moving said pilot valve to open the same, then to open said main valve head and thereafter to open said throttling port to said delivery port.

7 5. A throttling device having a valve casing provided with a pressure fluid supply chamber and a delivery port, a valve having sliding movement in said casing and normally closing said delivery port but provided with a throttling port adapted to open and close said delivery port, a main valve having a seat in said supply chamber against which it is pressed when in closed position by the pressure in said chamber, the opening of said main valve serving to open the supply cham- 7 her to free communication with said slide valve,

a pilot valve movement of which effects a condition of substantial pressure balance on said main valve, and actuating means for first opening said pilot valve, then openingsaid main valve and thereafter opening said throttling port to said delivery port.

6. A throttling device having a valve casing provided with a pressure fluid supply chamber and a delivery port, a throttling valve normally closing said delivery port but movable to open and close the same and to control the throttled supply of pressure fluid to said delivery port, a main valve having a seat in said supply chamber against which it is pressed when in closed position by the pressure in said chamber, the opening of said main valve serving to open said supply chamber to free communication with said throttling valve, a pilot valve movement of which efiects a condition of substantial pressure balance on said main valve, and actuating means for first opening said pilot valve, then said main valve and thereafter opening said delivery port through said throttling valve.

7. A throttling device having a valve casing provided with a pressure fluid supply chamber and a delivery port, a throttling valve normally closing said delivery port but movable to open and close the same and to control the throttled supply of pressure fluid to said delivery port, a main valve having a seat in said supply chamber against which it is pressed when in closed position by the pressure in said chamber, the opening of said main valve serving to open said supply chamber to free communication with said throttling valve, a pilot valve, movement of which effects a condition of substantial pressure balance on said main valve, and actuating means for first opening said pilot valve, then said main valve and thereafter opening said delivery port through said throttling valve, said actuating means having an actuating member passing through a packed aperture in the casing, the packing of which is exposed to pressure only on the delivery port side of said main valve.

8. A throttling device having a valve casing provided with a pressure fluid supply chamber, a delivery port and an intermediate supply chamber, a main valve between the supply chamber and intermediate chamber and having a seat in the supply chamber against which it is pressed when in closed position by the pressure in said supply chamber, the opening of said main valve serving to place said supply chamber in free communication with said intermediate chamber, a throttling slide valve between the intermediate chamber and delivery port and normally closing the latter to the intermediate chamber, a pilot valve, movement of which effects a condition of substantial pressure balance on the main valve, and actuating means movement of which operates to first open the pilot valve, then the main valve and thereafter to move said throttling valve to uncover said delivery port to said intermediate chamber.

GEORGE A. CROSBY. 

